Operating arrangement for hydraulic drives



Original Filed Oct. 24 1951 OPERATING ARRANGEMENT FOR HYDRAULIC DRIVES 4 Sheets-Sheet l F/Lii.

INVENTOR. OTTO H UBL/IY e- BY 0. NUBLING OPERATING ARRANGEMENT FOR HYDRAULIC DRIVES May 25, 1954 4 Sheets-Sheet 2 Original Filed Oct. 24, 1951 F/E.Z.

INVENTOR. OTT DBL-HYG- BY y 1954 o. NUBLING OPERATING ARRANGEMENT FOR HYDRAULIC DRIVES 4 Sheets-Sheet 5 Original Fi led Oct. 24 1951 INVENTOR. OTTO NO8LIII9 II/fill! May 25, 1954 NUBUNG 2,679,300

OPERATING ARRANGEMENT FOR HYDRAULIC DRIVES Original Filed Oct. 24, 1951 4 Sheets-Sheet 4 IN VEN TOR. 0W0 Nu 8 1.1/16- W/j? 11,, W.

Patented May 25, 1954 OPERATING ARRANGEMENT FOR HYDRAULIC DRIVES Otto Niibling, Bremen-Huchting,

Germany, as-

signor to Firma Theodor Klatte, Bremen- Huchting, Germany Original application October 24, 1951, Serial No.

252,961. Divided and this application January 9, 1952, Serial No. 265,695

Claims priority, application Germany October 24, 1950 6 Claims.

This application is a divisional application of my pending U. S. application Serial No. 252,961, filed October 24, 1951, entitled Hydraulic Drives For Vehicles.

The present invention relates to an improvement for hydraulic drives for vehicles, and more particularly to an operating arrangement for inactivating a hydraulic motor driving a single wheel of a vehicle by turning a control valve associated by servomotors.

Hydraulic drives for vehicles are known in which each wheel of the vehicle is separately driven by a hydraulic motor while all hydraulic motors are supplied with an operating liquid by a single pump.

In the event that a vehicle driven by a hydraulic drive of this type rests with one wheel on a slippery ground, or in the event that one of the wheels cannot exert any traction due to an uneven surface of the ground, the respective wheel will spin at an excessive speed, while all other wheels cannot exert any traction since the pressure of the liquid supply drops. This efiect is comparable to differential effect occuring in vehicles provided with differential gears.

It is an object of the present invention to overcome this disadvantage and to provide means for separating the hydraulic motor of a spinning wheel from the hydraulic drive of the vehicle.

It is another object of the present invention to provide a control valve in each hydraulic motor which permits separating of the hydraulic motor from the supply of operating liquid while at the same time permitting rotation of the wheel when the vehicle is moved by the action of the other wheels.

It is a further object of the present invention to provide means for adjusting the control valves independently of each other for separating a spinning hydraulic motor and associated wheel from the supply of operating liquid.

It is a still further object of the present invention to provide a servomotor for adjusting each control valve in accordance with the pressure in the associated hydraulic motor.

it is a still further object of the present invention to provide an auxiliary motor which is manually actuated by a three-way valve and adapted to override the regulating action ofThe servomotor by turning the control valve into a position in which the associated hydraulic motor is separated from the supply of operating liquid.

With these objects in view, the present invention is applied to a vehicle having a set of wheels and provided with a pump, drive means for driving the pump, a set of hydraulic motors driven by the pump, each of the hydraulic motors being associated with one of the wheels for driving the same, and mainly consists of a plurality of control valves which communicate with the pump on one hand and with one of the hydraulic motors on the other hand. Each of the control valves may be operated independently of the other control valves and is movable from an operative position-permitting supply of an operating liquid to the suction side of the corresponding hydraulic motor and discharge of the liquid from the pressure side thereofto an inoperative position in which the pressure and the suction side of the corresponding hydraulic motor are connected by the control valve.

In inoperative position the control valve permits unhindered circulation of the operating liquid in the hydraulic motor without supply and discharge of the operating liquid.

Furthermore, means are provided for separate- 1y operating a control valve when surface conditions of the ground cause spinning of a wheel. When the control valve of the spinning wheel is placed in inoperative position, the hydraulic motor is separated from the pump so that the other hydraulic motor can exert traction and move the vehicle. Since the circulation within the hydraulic motor is not hindered, the hydraulic motor and the associated wheel are freely rotatable and rotate while the vehicle is moved by the action of the other hydraulic motors and wheels until the separated hydraulic motor is again connected to the pump by moving the control valve into operative position by a suitable means.

Manually operable means may be provided for operating any one control valve, and indicating means may indicate to the operator of the vehicle which of the wheels is spinning.

Preferably the control valves are not directly operated by manually operable means. It is known to provide a hydraulic motor with a servomotor for operating the associated control valve. A servomotor of this type is automatically regulated in accordance with the pressure in the associated hydraulic motor so as to actuate the control valve. According to a preferred embodiment of the present invention an auxiliary servomotor is provided which, during operation thereof, engages the movable member of the automatically controlled servomotor so as to override the regulating action of the same caused by pressure changes in the hydraulic motor, and to move the movable member of the servomotor to a position in which the control valve is turned into an inoperative position separating the associated hydraulic motor from the supply of operating liquid.

Preferably hydraulic motors of a known type are used which consist of an outer rotatable element having an inner gear engaging an outer gear on an inner rotatable element. The control valve is arranged in the interior of the inner rotatable element, while the outer rotatable element is secured to the inside of the rim of the wheel.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional View of a hydraulic motor according to the present invention;

Fig. 2 is a cross-sectional view of a hydraulic motor mounted in a vehicle wheel;

Fig. 3 is a cross-sectional view of a hydraulic motor showing the control valve in another position; and

Fig. 4 is a diagrammatic view of an arrangement according to the present invention.

Referring now to the drawings, Figure 1 shows a hydraulic motor built into a wheel 2. The operating liquid is supplied and discharged by the control valve 3 through two separate conduits 4 of which only one can be seen in Fig. l. The operating liquid is guided through slots 5 to the chambers 6 of a rotary hydraulic gear motor. For regulating the motor the control valve 3 is turnable through approximately 90.

The operation of the hydraulic motor can be better understood from Figs. 2 and 3 which show the arrangement of the rotary hydraulic gear motor in cross-section. A rotatable hollow inner member I is surrounded by an outer annular member 8 which is rotatably mounted eccentrically thereto. The inner member I is provided on its perimeter with a plurality of teeth meshing with inner teeth on the outer annular member 8. The number of teeth of the hollow inner member I is one less than the number of teeth of the outer annular member. The depressed portions between the teeth of the inner and the outer members form together chambers Ni, ii, i2 and 53. During rotation in the direction of the arrow the chambers l3 and i I are increasing in volume while the chambers l0 and I2 are decreasing in volume. The control valve 3 does not rotate with members 1 and 8 but is turnable on shaft in the interior of the inner member I from a position in which the free wall portions 9 extend in the direction of the eccentricity as shown in Fig. 3, to a position normal thereto, as shown in Fig. 2.

Fig. 3 shows a control valve 3 with channels t and 36 to which the operating liquid is supplied and discharged respectively by means of bores 31 and 38.

In the normal position of shown in Fig. 3, the free wall control valve 3 extend in eccentricity and the supplied operating liquid forces the chambers 3i to increase in volume whereby both members 1 and 8 are rotated. The chambers 32 which are decreasing in volume press the operating liquid back into the discharge the control valve portions 9 of the the direction of the conduit. Fig. 2 shows the control valve 3 turned through an angle of so that the free wall portion 9 extends normal to the eccentricity. In this position the operating liquid pressed out of chambers l0, flows into the chambers H, and the liquid pressed out of the chambers 12 flows into the chambers l3. Since the quantity of operating liquid displaced out of chambers i3 and i2 is the same as the quantity sucked into chambers II and I3, no operating liquid can be supplied to or discharged from the hydraulic motor, and consequently no power is transmitted to the wheel to which the outer member 3 is fixedly secured. However, the wheel is freely rotatable, since the resistance against rotation caused by the inner circulation of the operating liquid from chambers IE and 2 to chambers H and I3 is only small.

In the intermediate positions of the control valve 3 only a part of the operating liquid circulated within the chambers between the inner and the outer members while another part thereof is supplied and discharged through bores 3? and 38, respectively. By turning the control valve to an intermediate position, the speed of rotation of the hydraulic motor and of the vehicle may be regulated in a known manner. The pres-- ent invention is only concerned with an arrangement for placing the control valve into the inactivating end position shown in Fig. 2 for separating a wheel spinning at an excessive speed.

Fig. 1 shows an embodiment according to which the control valve 3 may be turned by means of a bevel gear M which is fixedly secured thereto. A servomotor I5 is fixedly connected to a rack bar it which engages a pinion I! which is connected for common rotation with a coaxial bevel pinion I'! meshing with the bevel gear M. When the servomotor is operated, the valve is turned into a position between the two positions shown in Figs. 2 and 3 for regulating the speed of the hydraulic motor.

For overriding the action of the regulating means an auxiliary piston I8 is provided. When a valve 19 is opened, operating liquid is supplied through the conduits 49 and 20 and urges the piston I8 to the left of Fig. 1. The piston 18 engages a sleeve I5 and also the valve control bar l5 of the servomotor i5 and moves the servomotor l5 and the rack bar it connected thereto to the left of Fig. 1, whereby pinions H. H and bevel gear M are rotated and turn the control valve in the position shown in Fig. 2, in which the hydraulic motor is separated from the supply and discharge of operating liquid.

The bore 4] communicates permanently with the pressure oil conduit to the oil engine. The pressure oil flows through the annular spaces 42 and 43 and the bores 44 and 45 to the control slide valve 46, which governs the movement of the piston I5 and turns the control valve 3 for regulation through the gear wheels I! and 14. The control slide valve 46 has the secondary task to return the auxiliary piston I8 into the starting position. It is provided with two inner control pistons 41 and 68, which differ from each other in diameter and slide on stepped cylindrical inner face portions. Valve I9 is a three-way selector cook. The discharge pipe 50 is opened as the supply conduit 49 is shut off by valve l9. Now the pressure oil entering through the bore 4| presses upon the differential annular surface formed by the inner pistons 41 and 48 and thus urges" the slide valve 46 and the auxiliary piston 18 right-hand into the starting position. The

oil displaced by piston I 8 is discharged through conduits 20, 49 and discharge conduit 50. As the annular surface of piston I8 is by far larger than the effective face of the slide valve 46, a sufiiciently great excess power will arise after opening the valve [9 to move the slide valve lefthand, even if the bore 4| should be under pressure After cutting in the differential pawl the piston 58 abuts against the sleeve I5 of part [5. The oil ducts 5| and 52 are thereby cleared by the control pistons 41 and 48, so that pressure oil from bore M can penetrate into the annular space 53. Consequently the eifort of piston I8 will cooperate with that of piston [5 in order to move the rack I 6 and to turn the slide valve 3.

Fig. 5 shows the arrangement of the hydraulic drive diagrammatically. A pump 44 supplies and discharges the operating liquid through conduits 40 to the hydraulic motors 4| which are built into the wheels of a vehicle. A conduit 42 supplies liquid to the spring loaded valve [9 which may be opened by manually operable means, for instance by a wire 43 guided around pulleys 43. When the valve I9 is opened, the liquid passes through conduit 49' and 29, to the auxiliary piston 18 for operating the control valve 3 by means of a servomotor l5, the rack bar I 6, the gear means I! and the bevel gear M as shown in Fig. 1.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of drives for vehicles diifering from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for separating a hydraulic motor driving a single wheel of a vehicle from the supply of operating liquid when ground conditions cause excessive rotary speed of hydraulic motor by turning a control readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. An operating arrangement for a hydraulic motor, comprising in combination, a turnable control valve for regulating said hydraulic motor; a hydraulic servomotor including a movable membet; gear means operatively connecting said movable member of said servomotor with said control valve for turning the latter; conduit means connecting said servomotor with said hydraulic motor for supplying liquid from said bydraulic motor to said servomotor for moving said movable member according to the hydraulic pressure in said hydraulic motor; an auxiliary servomotor including movable means engaging said movable member during movement in one direction so as to override the movement of the same caused by said liquid supplied from said hydraulic '6 motor through said conduit; a conduit communicating with said auxiliary servomotor; a discharge conduit; vand a three-way valve in said conduit movable between two positions and in one position opening said conduit for passage of a liquid under pressure to said auxiliary servomotor, and in the other position thereof closing said conduit and connecting said auxiliary servomotor to said discharge conduit.

2. An operating arrangement for hydraulic motors according to claim 1 and including spring means urging said movable means of said auxiiiary servomotor in said one direction.

3. An operating arrangement for a hydraulic motor comprising in combination, a turnable control valve for regulating said hydraulic motor; a hydraulic servomotor including a cylinder, a hollow piston member slidably' mounted in said cylinder and having in the interior thereof two co-axial stepped cylindrical face portions, said piston member dividing said cylinder into two chambers and being formed with two ducts, each duct connecting one of said chambers with the interior of said hollow piston member, each duct opening in a port on one of said stepped cylindrical race portions, a control slide valve mounted slidably in the interior of said piston member and having two spaced control pistons having different diameters, each control piston sliding on one of said stepped cylindrical face portions and adapted to cover said ports of said ducts; gear means operatively connecting said hollow piston member with said control valve for turning the latter; an auxiliary servomotor including a cylinder coaxial with said cylinder of said servomotor, an auxiliary piston slidably mounted in said cylinder and secured to said control slide valve so as to move the latter and to uncover said ports, and engaging said hollow piston member during movement in one direction and moving the same so as to eifect turning of said control valve; sprin means urging said auxiliary piston and said control slide valve in said one direction; conduit means connecting the space in the interior of said piston member between said spaced control pistons of said slide valve with said hydraulic motor for supplying hydraulic liquid from said hydraulic motor to said servomotor for moving said slide valve in a direction opposite to said one direction according to the pressure in said hydraulic motor, the control piston of said control slide valve located adjacent to said auxiliary servomotor having the larger diameter; a conduit communicating with said cylinder of said auxiliary servomotor and adapted to supply liquid under pressure thereto for moving said auxiliary piston in said one direction; a discharge conduit; and a three-way valve in said conduit movable between two positions and in one position opening said conduit for passage of lit did to said auxiliary servomotor, and in the other position thereof closing said conduit and connecting said auxiliary servomotor to said discharge conduit.

4. An operatin arrangement for a hydraulic motor, comprising in combination, a turnable control valve for regulating said hydraulic motor; a hydraulic servomotor including a cylinder, a hollow piston member slidably mounted in said cylinder and having a projecting sleeve portion projecting out of said cylinder, said piston member dividing said cylinder into two chambers and being formed with two ducts, each duct connecting one of said chambers with the interior of said hollow piston member, said hollow piston member having in the interior thereof two coaxial stepped cylindrical face portions, the wider cylindrical face portion extending into said sleeve portion, each of said ducts opening in a port on one of said stepped cylindrical face portions; 2. control slide valve mounted in the interior of said piston member and having two spaced control pistons havin difierent diameters, each control piston sliding on one oi said stepped cylindrical face portions and adapted to cover one of said ports of said ducts, said control slide valve having a projecting portion extending within said projecting sleeve portion of said hollow piston member; conduit means connecting the space in the interior of said piston member beween said spaced control pistons of said slide valve with said hydraulic motor for supplying hydraulic liquid to said servomotor for moving said slide valve in the direction of the larger of said tWo control pistons of said slide valve; gear means operatively connecting said piston member with said control valve for turning the latter; an auxiliary servomotor including a cylinder, and an auxiliary piston slidably mounted in said cylinder and secured to said projecting portion of said control slide valve spaced a short distance from the end of said projecting sleeve of said piston member so that during movement of said auxiliary piston toward said servomotor said slide valve uncovers said ports and liquid passes from said space between said control pistons through one of said ducts into one of said chambers so as to move said piston member whereupon said auxiliary piston engages said sleeve portion of said piston member so as to move said piston member and to effect turning of said control valve; spring means urging said auxiliary piston to move toward said piston member; a conduit communicating with said cylinder of said auxiliary servomotor and adapted to supply liquid thereto for moving said auxiliary piston toward said piston member; a discharge conduit; and a three-way valve in said conduit movable between two positions and in one position opening said conduit for passage of liquid to the cylinder of said auxiliary servomotor, and in the other position thereof closing said conduit and connecting said auxiliary servomotor to said discharge conduit.

5. In a driving arrangement for a vehicle having a set of wheels, each wheel separately driven by a hydraulic motor, an operating arrangement for each of said hydraulic motors, comprising in combination, a control valve turnably mounted in one of said hydraulic motors and in one position inactivating said hydraulic motor; a servomotor including a piston and a cylinder, the latter communicating with the pressure side of the associated hydraulic motor for moving said piston according to the pressure in the associated hydraulic motor; gear means connecting the piston of said servomotor with said control valve for turning the same when said piston moves; an auxiliary servomotor including a cylinder, and a piston connected to said piston of said servomotor for common movement; conduit means supplying operative liquid under pressure to said cylinder of said auxiliary servomotor; a discharge conduit; and a three-way valve located in said conduit movably between two positions, and in one position permitting passage of operative liquid under pressure to said cylinder of said auxiliary servomotor so as to move the piston of the same, and thereby said piston of the associated servomotor so as to turn said control valve to said position inactivating said hydraulic motor, and in a second position closing said conduit and connecting the cylinder of said auxiliary servomotor to said discharge conduit permitting discharge of liquid from the cylinder of said auxiliary servomotor so that said servomotor returns said piston of said auxiliary servomotor to said inoperative position.

In a driving arrangement for a vehicle having a set of wheels, said driving arrangement including a pump, drive means driving sai pump, a set of hydraulic motors driven by said pump, each of said hydraulic motors associated with one of said wheels for driving the same, in combination, a plurality of control valves, each of said control valves communicating with said pump on one hand, and with one of said hydraulic motors on the other hand, each of said control valves being movable independently of the other control valves from a normal position supplying and discharging an operative liquid to the corresponding hydraulic motor to inactivating position connecting the pressure side and the suction side of said hydraulic motor and disconnecting the same from said pump; a set of servomotors, each of said servomotors including a piston and'a cylinder, the latter communicating with the pressure side of one or" said hydraulic motors so that said piston moves according to the pressure in the associated hydraulic motor; gear means operatively connecting the piston of each of said servomotors with the control valve of the associated hydraulic motor for turning said control valve; a set of auxiliary servomotors each including a cylinder, and a piston connected to the piston of one of said servomotors and movable between an inoperative position and an actuating position; a plurality of conduit means, each of said conduit means connecting the pressure side of said pump with the cylinder of one of said auxiliary servomotors; and a plurality of manually operable three-Way valves, each of said three-way valves located in one of said conduits movably between two positions, and in one position permitting supply of operative liquid under pressure to one of said auxiliary servomotors so as to move the piston of the same to said actuating position for actuating and moving the piston of the associated servomotor and for turning the associated control valve into said inactivating position, and in the second position disconnecting said auxiliary servomotor from said pump and permitting discharge of liquid from said auxiliary servomotor so that the automatic action of the associated servomotor returns said auxiliary servomotor to inoperative position and said control valve to said normal position.

References Cited in the file of thi patent UNITED STATES PATENTS Number Name Date 2,139,965 Ljungstrom Dec. 13, 1938 2,365,095 Miller et al Dec. 12, 1944 2,475,105 Mitton 1 July 5, i949 

